132 MOEPHOLOGT AXD EVOLUTION shallow sigmoid notch separates the recurved coronoid process from the eondyle. The coronoid process is loftier than the eondyle, unlike that in Man. The symphysis rnenti is receding and bears a genial ridge on its posterior surface. The digastric and mylo-hyoid impressions are slight, but the latter is better marked than in the Chimpanzee. Tlv ai'iill of the Gurilla differs from that of the Orang, 11 n I approaches the human skull in the folio icing characters :— 1. The cranial part is larger in proportion to the facial part. 2. The foramen rnagnum is more advanced in position. 8, The supra-occipital forms a smaller angle with the basi-occipital. 4. The rnastoids are processes instead of rough rid'.ges. 5. There is a vaginal process. i ti. The glenoid cavities are deeper. 7. The posterior nares are wider. s. The zygomata are shorter and straighter. 9. The foramen ovale more completely perforates the alisphenoid. 10. Spheno-maxillary fissure is wider. 11. The orbits are squarer. 12. The upper parts of the nasal bones are more promi- nent. IS. The muzzle is narrower and less produced. 14. The inter-orbital width is greater. 15. The sella turcica is wider. 16. There are true frontal sinuses. 17. The orbital roofs are not so convex. The Orang differs from the Gorilla and approaches Man more closely in the following characters :— 1. The calvarium is more convex, 2. The supra-orbital crests are smaller and separate. 3. The formation of the pterion.